@phdthesis{Eichler2005,
  author    = {Eichler, Lars},
  title     = {Effects of desialyation on TCR-cross-linking and antigen sensitivity of CD8 positive T lymphocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-19391},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {The featured experiments focus on changes in T cell membrane glycosylation as a possible means of controlling TCR cross-linking. Taking the long known fact that activated T cells show decreased levels of surface sialic acid as a starting point, differences in ligand binding and cellular reaction upon in vitro stimulation were investigated in na{\"i}ve, activated and enzymatically desialyated CD8+, 2C TCR transgenic mouse lymphocytes. To detect differences in ligand binding lymphocytes were incubated with various concentrations of fluorescently labeled, soluble MHC/Ig fusion proteins until equilibrium was reached. Without previous washing, cells were analyzed by flow cytometry, determined MCF values were normalized to the plateau and fit to a mathematical model of equilibrium binding of divalent ligands to monomorphic receptors (Perelson 1984). Parameters derived from the model fit of binding data show, that neuraminidase treatment of T cells was sufficient to mimic a partially activated phenotype, showing enhanced TCR cross-linking. Enhanced TCR cross-linking was found to be dependent on the presence of CD8, as neuraminidase treatment of DN cells lead to decreased cross-linking. To elucidate the physiological relevance of desialyation induced increases in TCR cross-linking early tyrosine phosphorylation events and proliferative response upon in vitro stimulation of T cells were investigated. Both were found enhanced in neuraminidase treated cells, as compared to native cells. In conclusion the featured experiments suggest a role of surface sialic acid in controlling TCR cross-linking on na{\"i}ve and activated T cells.},
  language  = {en}
}